Signaling system



Aug. 19,v 1947. H. HANLEY SIGNALING SYSTEM original Filed Aug. 12, 194s ATTORNEY Patented ug. 19, 1947 i SIGNALING SYSTEM Frank Harold Hanley, Butler, N. J., assignor to American Telephone and Telegraph Company, a corporation of New York Original application August 12, 1943, Serial No.

4 Claims.

This invention relates to signaling systems and, more particularly, to apparatus for transmitting signals between two or more stations so that the signals may be rendered visible at the stations. Still more particularly, this invention relates to apparatus for transmitting groups of pulses from one station to one or more other stations in accordance with predetermined signals or characters, the apparatus including means at the receiving station r stations for converting the various groups of pulses corresponding to the signals or characters into visual signals or characters so that they may be observed and read at the receiving station or stations.

There are different types of equipment available for handling communications between telephone or telegraph ofiices. These include manual telegraph systems, teletypewriter systems and telephone systems. Manual telegraph systems usually contain simple parts and are therefore less costly than the other systems for 4simple routine communications. Hence such systems are used more frequently than the others. Teletypewriter systems embody more expensive apparatus, and it is Often impractical to employ such apparatus at places where communication facilities are required. However, the use of manual telegraph systems for interoflice communication has fallen oir recently because of the shortage of Morse operators, and because of the length of time required to train operators in the technique of sending and receiving Morse code signals.

Accordingly it is an object of this invention to provide simple and economical communication apparatus which will not require Morse operators or other skilled personnel. The arrangement of this invention in general consists of a transmitter having a start-stop distributor controlled by a plurality of non-locking push button keys arranged so that the operation of any key may produce two (or more) pulses, for example, a spacing pulse followed by a marking pulse, for transmitting a predetermined character or signal to a distant receiving point. The receiving apparatus involved in the invention may include a startstop distributor, a scanning disk having transparent characters and aneon tube associated with the -distributor and the scanning disk for furnishing illumination for the characters to be illuminated at the receiving station. The receiving apparatus is arranged to respond to the groups of pulses received and illuminate the character or signal defined by the pulses. The system 'differs from the usual teletypewriter sys- Divided and 1944, Serial No. 545,864 4 this application July tem in that simpler codes are used to convey the signals or characters and, moreover, the signals or characters reproduced by the receiving apparatus are not recorded but are made visible for a brief interval of time. The receiving attendant will observe each lcharacter illuminated by the neon tube, and as the desired character appears before the scanning disk, it will be the only one illuminated at the receiving point.

In the apparatus used to carry out the invention about half of the characters may be transmitted by means of codes 0r signals having but two pulses which will be referred to as twotransition codes. The first pulse of a twotransition code will be a spacing pulse, and it Will be followed by a marking pulse. The overall length of the two pulses forming the code may 'be constant, but the relative lengths of the marking and spacing pulses will differ from each other for the diierent characters. The other half of the characters may be transmitted by means of codes having four pulses which will be referred to as four-transition codes. The pulses forming the characters transmitted by four-transition codes include a spacing pulse, a marking pulse, a second spacing pulse and a second marking pulse. The first two pulses of the four-transition codes are short pulses of equal duration but the second spacing pulse generally will be of a different length from the second marking pulse. The relative lengths of the second spacing and marking pulses will be different from each other for the 'different characters transmitted by four-transition codes.

When lconsidered from a. different point of view, the transmitting apparatus may be thought of as producing different groups of pulses for the different characters to be transmitted. For the two-transition types of codes, the two pulses deiining each character are of relatively dierent lengths, although the overall lengths of the pulses of the various groups are the same, The receiving apparatus includes a rotary device having the various characters displayed along its periphery at 'different peripheral distances from a xed or predetermined point. The circumference of the rotary device may be looked upon as divided into two parts, which are proportional to the lengths of the two pulses defining that character. The reception of the first pulses will start the rotary device in rotation past the fixed or predetermined point and at the same time cause a condenser to be charged. At the end of the first pulse, or at about the beginning of the second pulse, the condenser will be discharged at a rapid rate into a circuit including a gas tube of the neon type, causing the neon tube to be illuminated and to illuminate for a brief interval of time the `desired character approximately at the time when that character passes the Iixed or predetermined point. The attendant may then observe and read the transmitted character.

This application is a division of my copending application Serial No. 498,268, led August 12, 1943, entitled Signaling system.

This invention will be better understood from th'e more detailed description hereinafter following when read in connection with the accompanying drawing in which Figure 1 represents a keyboard such as may be found in the usual typewriter or teletypewriter, the keys of which are of a non-locking type, Fig. 2 shows a circuit arrangement of the invention in which the sending unit is illustrated in some detail, and Fig. 3 shows an arrangement similar to that of Fig. 2, except that the receiving unit is here shown in considerable detail.

'The keyboard shown in Fig. 1 includes a plurality of non-locking keys such as may be found in the usual typewriter. These keys are employed to control the operation of the circuits of Figs. 2 and 3. Fig. 2 shows a station A at the left connected by a line LL to a station B at the right. These stations are also shown in Fig. 3 interconnected by the line LL. Each station may include both a sending unit and a receiving unit so that signals or characters may be transmitted in both directions between the stations. In Fig. 2 the sending unit is designated YSU and the receiving unit is designated YRU. In Fig. 3 the sending unit is designated ZSU and the receiving unit ZRU.

The various keys of the keyboard of Fig. 1 control corresponding contacts of the sending unit YSU. For example, the key Q of Fig. 1 may control the contact YQ of Fig. 2. When key Q is depressed, the contact YQ will be opened and held open as long as the key Q remains depressed. Likewise keys W, E, R, T, Y, etc. of Fig. 1 control the respective contacts YW, YE, YR, YT, YY, etc. of Fig. 2. The contacts YQ, YW, YE, etc. are shown for illustrative purposes positioned about the axis of the brush arm YBA forming the inner periphery of key-controlled contacts, while other contacts such as YI, Y2, Y3, Y, Y5, etc., which are also controlled by corresponding keys l, 2, 3, 5, etc. of the keyboard of Fig. 1, are likewise shown concentrically about the shaft ofthe brush arm YBA and form the outer periphery of keycontrolled contacts.

The transmitting apparatus YSU (sce Fig. 2) includes a distributor having a continuous inner segment YSS and a plurality of outer segments such as YST, YSH, YQI, YW2 YKL which are positioned adjacent to each other. A brush arm YBA controlled by magnet YM may be a1- lowed to sweep over these segments of the distributor to produce groups of pulses corresponding to the various characters to be transmitted, as will be explained later. It will be observed that the contacts YQ, YI, YW, Y2, YE, Y3 YK, YL, are wired in series relationship with each other. This series circuit includes the winding of the relay SR and the magnet YM of the receiving unit YRU. This series circuit is connected by. means of the line LL to the apparatus at.the distant station B.

The receiving apparatus ZRU which is shown more fully in Fig. 3, includes, among other things,

a rotary device upon which is mounted a scanning disk SD amxed to a brush arm ZBA. The receiving unit also includes a condenser C and a neon tube ZT, which is positioned behind the scanning disk SD and will become illuminated by the discharge of condenser C in response to a signal or character received. The tube ZT will light up the desired signal or character received so that it may be observed and read by the attendant. The receiving unit ZRU also includes a distributor having a continuous inner segment ZSS and a plurality of small outer segments, such as ZST, ZSH, ZQI, ZW2 ZKL, which are arranged concentrically about the axis of the brush arm ZBA.

lThe brush arms YBA and ZBA at any one station, although shown and described hereinafter as separate and distinct elements, may, however, be thesame element and this element may be controlled by the magnet such as YM of the station, as will be explained hereinafter. The brush arms YBA and ZBA are assumed to be connected to a suitable motor through a friction clutch (not shown) as will be understood by those skilled in the art.

When one of the keys, such as key Q, for example, of the keyboard of Fig. l, is depressed, the Contact YQ will be opened so as to interrupt the flow of current through the winding of relay SR and through the winding of magnet YM and over line LL to station B. This circuit will be held open as long as the key Q remains depressed. The absence of current over the line LL upon the depression of the key Q will cause the receiving relay RR at station B to move its armature to its spacing contact S and the magnet ZM at the same station will release. Considering for the moment the apparatus at the sending station A of Fig. 2, it will be observed that the release of the relay SR. will connect the positive potential of battery B1 to the continuous segment YSS over a circuit which includes the armature and back contact S of relay SR and resistor R1. The release of the magnet YM will unlatch the brush arm YBA and allow it to revolve in a clockwise direction. As the brush YB! affixed to brush arm YBA passes over segments YST and YSH, the line LL will be kept open to prevent the flow of current to the apparatus at station B. As the brush YBl contacts segment YQI, however, the battery B1 previously connected to the continuous segment YSS by the armature and contact of relay SRlv will be connected to the line LL and to the apparatus at station B. The circuit extending to line LL and to the apparatus at station B includes battery B1, the armature and back contact S of relay SR, resistor R1, the continuous segment YSS, brush' YBI, segment YQI, the contacts YW, Y2, YE, Y3, YR, YQ, YT, YS YK, YL, the magnet YM of the receiving unit YRU and the line LL which extends to station B. The apparatus at station B terminates in a negative battery B2 which is poled in series aiding relation to battery B1. Thus, as the brush YBI contacts segment YQl, a substantial potential will be applied to the line LL and current will iiow over this line to the distant station B. As the brush YBI passes over each additional segment YW2, YES, YR4, YT5, YYG YKL, the voltage of battery B1 will remain applied to line LL through the armature and back contact S of relay SR, thereby holding the line LL closed for the remainder of the revolution of the brush arm YBA.

It will be observed that in response to the depression of the key Q of Fig. l the contact YQ is opened to interrupt the flow of current over line LL and that as the brush YBl contacts the segment YQl, battery B1 is connected to the line LL and remains connected to the line LL to allow a substantial flow of current thereover. The interruption of the flow of current over line LL produces a spacing pulse, and the subsequent closure of the line LL produces a marking pulse. The spacing pulse lasts for about two units of time, for example, while the corresponding marking pulse lasts for at least eighteen units of time. Thus the letter or character Q may be conveyed to the distant station B by means of a twotransition code, as already referred to. When the key W of Fig. l is depressed by the operator, the contact YW will be opened instead of the contact YQ, and hence a two-transition code consisting of a spacing pulse of about three units and a corresponding marking pulse o1" at least seventeen units will be transmitted over the line LL to the apparatus at station B. The character E may likewise be conveyed to the distant station B by a spacing pulse of four units anda corresponding marking pulse of at least sixteen units, and so on. Each of these characters is defined by two pulses which are relatively different from each other, but the overall lengths of the various pairs of pulses are the same.

It is observed that the magnet YM of Fig. 2 is connected in series with the line LL so that the current that iiows over the line LL also traverses the winding of the magnet YM. Hence as soon as the battery B1 is connected to the line LL the magnet YM will become re-energized. The reenergization of the magnet YM will cause its latch to drop into its normal position to prevent the further rotation o the brush arm YEA after it has completed one revolution. lt is also noted that the relay SR will be released. only as long as one of the keys of the keyboard remains depressed. As soon as the key is released, the winding of relay SR will become re-energized so as to cause its armature to close its contact M. The operation of relay SR will remove the resistor R1 from the circuit so that the sending apparatus will be ready for the transmision of another character.

The relay SR is adjusted so as to be slightly slower to release than magnet YM, the release of the relay being completed before brush Y'Bl leaves segment YST. Consequently, upon the depression of one of the keys of thel keyboard, such as key A, the series circuit including the windings of relay SR. magnet YM will be opened, al

lowing the brush arm YEA to start to rotate just before the armature of relay SR. releases to close its back contact S. Upon the closure of contact S by the armature of slow/release relay SR, ba"- tery B1 will be connected through resistor R1 to the continuous segment YSS. ience, when brush YBl reaches the segment YAZ. current will again traverse the winding of magnet YM, as already explained. This circuit may be traced from batn tery B1, the armature and contact S oi relay SR, resistor R1, continuous segment YSS, brushes YBl or" brush arm YBA, segment YAZ, contacts YS, YX, YD, YC, Yi, magnet and line LL to station E and battery B2. This circuit will cause magnet YM to become 're-energized to attract its latch so as to prevent the brush arm YBA from rotating rn re thanone revolution even if the attendant holds the key A depressed longer than is required for the brush arm YBA to complete its revolution. Relay SR will become reoperated after the previously depressedV key A has been released. After relay SR operates in response to the release of the previously depressed key, the pulses corresponding to the same character or any other character may be transmitted by depressing the appropriate key of the keyboard.

Any one of contacts YQ, YW, YE, YR, YT YK, which are shown on the inner periphery of the sending unit YSU may be opened by the corresponding key of the keyboard of Fig. 1 for sending a two-transition code over line LL to the receiving' station B. The remaining contacts Yl, Y2, YB, Yl, YE YL shown on the outer periphery of the sending unit YSU are controlled by other keys of the keyboard of Fig. 1. When the key l or" Fig. l is depressed, the swinger of the contact Y! will be moved upwardly to close the upper contact (which is normally open) for transmitting coded impulses over the line LL. As the contact Y! becomes so operated, it will open the circuit of the line LL extending to station B, this circuit having been previously described with respect to the transmission of the character Q to the distant station B. As the magnet YM becomes released, the brush arm YBA will again rotate in a clockwise direction in the same manner as already described heretofore. As the brush YB! passes over segment YST, the line LL will be opened in the same manner as the line LL was initially opened when the key Q was operated.

When the brush YBi contacts segment YSH, battery B1 will be connected to line LL and station B over a circuit which includes, in addition to battery B1, the armature and back contact S` of relay SR., resistor R1, the continuous segment YSS, brush YBi, segment YSH, the contacts of Yi, contacts YW, Y2, YE, YS, YR, Ye YK, YL, magnet YlV', line LL and station B. This will close line LL and the line will remain closed during the remainder of the travel of brush arm YBA throughout its revolution. Thus the operation of key l will produce a spacing pulse followed pulses produced by operating key Q, but it will be shown hereinafter that the character I will be exhibited at the receiving station B.

When key 2 of Fig. 1 is closed, the swinger` of Contact Y2 will be moved upwardly to close its upper terminal (which is normally open). This will cause relay SR and magnet YM to release, as already described. The release of magnet YM LL. This will result in a spacing pulse. Battery B1 will be connected to line LL when brush YB! contacts segment YSH, the circuit to line LL being completed through segment YSl-l, contact Y2, contacts YE, YS, YR, Y4, YK, YL and the winding of magnet YM. This will result in a marking pulse. When brush YBl contacts segment YQI, the battery B1 will again be disconnected from line LL at the contacts Y2 and hence there will be another spacing pulse. When brush YBI then contacts battery B1 will again be connected to line LL, the circuit being completed through segment YW2, contacts YE, YS, YR, Y4, YT, Y5 YK, YL, magnet YM, and line LL. This will produce a second marking pulse. The circuit to line LL Awill remain closed during the remainder of the travel of brush YBI through itscycle. Thus the operation of key 2 will relafraaeo'fl sult in our pulses, i. e., spacing, marking, vspacing and marking pulses, the rst three of 'the pulses being substantially equal unit pulses while the fourth pulse will be a relatively long pulse of about seventeen units. -Similarly `when key 3 of Fig. 1 is depressed, the first two pulses will be substantially equal unit pulses, the third (spacing) pulse will be about two unitslong and the fourth (marking) pulse will lbe about sixteen units long. Other keys vassociated with the contacts of the outer periphery will cause the production of two unit pulses (spacing and marking pulses) followed by two longer Apulses of relatively different lengths.

At station B (Fig. 3) the various groups of pulses received-operate Ythe relay RR and cause its armature to follow these pulses. The armature of the relay RR will close its contact S when a spacing pulse is received and vits Contact M Iwhen a marking pulse is received. The segments ZQI, ZW2, ZES, ZRA, ZT5, ZY ZKL, although positioned concentrically about the aXis of the brush -arm ZBA and sepa-rated from each other, are nevertheless conductively connected to each other As the iirst or spacing pulse corresponding to the letter Q is received and the armatureof relay RR closes its contact S, the absence of current in the magnet ZM (due to the opening of the circuit of the line LL) will unlatch the brush arm ZBA to enable it to rotate in a clockwise direction. As the brush ZB2 contacts segment ZST-which is a short segment and is contact- Aed at about the time when the brush Y'BA at the transmitter YST-the condenser C will become charged to the positive voltage of battery B3. The charging circuit for condenser C includes battery Bs, resistor R3, segment ZST, brush ZB2, the continuous segment ZSS, and conductor YZKDs which is connected to the lower terminal of condenser C, the upper terminal of the condenser C being connected to ground through the armature and contact S of relay RR. The battery Bs will be disconnected from the condenser C immediately after the brush ZB2 leaves the segment ZST, but the positive potential applied to the condenser C will remain substantially unchanged. As the brush ZB2 next contacts the `segment ZSH-which is positioned so that vits contact with the brush ZB2 will occur at about the time when the brush YBI yat station A is half-way across the segment YSH-the negative 'battery B4 will then `be connected to the condenser C. The circuit to-condenser C now includes battery B4, resistor R2, segment lZSI-I, brush ZB2, continuous segment ZSS, the conductor ZKDa connected to the lowerterminal of condenser C, the upper =terminal of which-is still connected to ground through the-armature vand contact S or relay RR. As the latter-circuit interconnecting battery 'B4 to condenser C is'completed, the condenser -C ywill -rst discharge and then charge to the opposite ornegative potential of battery B4. 'When the brush arm`YBA at the transmitter reaches the segment YQI current will again flow over rthe `line ILL and ythrough the upper v.winding of relay RR as already .described hereinabove, -thereby causing the armature .of relay RR to close -its vcontact iM. At the same time the magnet ZM will be re-energized so asto lower its latch Ato its nor- :mal position Vto :prevent any further movement of 'the brush arm TZBA after it 'has completed a revolution'. -But it is Vnoted that the brush YB'I by a conductor ZKDi.

is half way across segment at the transmitter of Fig. 2 is vmidway through its segment 'YQI at the time when -brush ZB2 of Fig. 3 contacts segment ZQI. At that time 4conductor ZKDr will be effectively connected to the conductor ZKDa through the continuous segment ZSS. Consequently the resistor yR5 will be bridged across the condenser C, the bridging circuit including the armature and contact M of relay RR, the resistor R5, conductors ZKD2 and ZKDi, brush ZB2, continuous segment ZSS and conductor ZKDs.

It is noted also that the two electrodes of the neon tube ZT are bridged across the resistor R5. Thus both the tube ZT and the resistor R5 are shunted across the condenser C at about the time when the vbrush ZB2 contacts the segment ZQI. The condenser C is, therefore, discharged at a very rapid rate. In discharging the upper or positive terminal of the condenser will be connected to the upper terminal or electrode of the tube ZT, while the lower or negative terminal of the condenser C will be connected to the lower terminal or electrode of the tube ZT. The application of a voltage of such polarity to the electrodes of the tube ZT will cause the upper electrode of the tube ZT to become luminous, and the luminosity will remain substantially the same until the voltage on the condenser C is reduced below the voltage required to sustain ionization fwithin the tube ZT. The time during which the upper electrode of tube ZT remains luminous depends on the constants of the discharge circuit and tube ZT.

It will be remembered that the scanning disk -SD is Xedto the brush arm ZBA so that both rotate together about their common axis. It follows, therefore, that when the brush arm ZBA contacts the segment ZQI, the letter Q of the scanning disk SD will then be positioned immediately infront oi' the upper electrode of the tube ZT which has just become luminous. Therefore, the letter Q will become visible to the attendant. The letter Q may be, for example, transparent so that the light emanating from the upper electrode oi tube ZT will freely traverse the transparent contour of'the letter. The letter Q will, therefore, be visible for a brief but appreciable period of time, an interval long enough to enable the attendant to observe it. Were the key W of Fig. 1 depressed instead of the key Q the condenser C at the receiver would discharge at about the time when the b-rush ZB2 contacted the segment ZW2. In this case, of course, the letter W of the scanning disk SD would be positioned adjacent to the upper electrode oi the tube ZT at the time when the upper electrode of tube ZT became luminous and then letter W would be visible to the attendant. And this is repeated for each of the other two transition codes transmitted from station A of Fig. 2 to station B of Fig. 3 to convey other characters such as E, R, T, etc. to the distant station B.

When the pulses corresponding to the character No. I are received at station B, the first spacing pulse (of unit length) will release the magnet ZM of Fig. 3, thereby permitting the brush arm ZBA to rotate clockwise. When the brush ZB2 contacts segment ZST, the positive potential of battery Bs will be applied to the lower terminal of condenser C over the same circuit previously described with regard to the response to the rst spacing pulse of the character Q. Upon the reception of the subsequent marking pulse from station A, relay RR will cause its armature to closeits contact M. When brush ZB2 contacts segment ZSI-I, the negative potential of battery B4 will be connected to the lower terminal of condenser C, but condenser C will not be discharged at that time. The reason for the positive charge remaining on condenser C is that the upper terminal of the condenser is not connected to ground through the armature and Contact S of relay RR and hence there is no complete discharge path for the condenser.

When the brush ZB2 thereafter contacts segment ZQi, the condenser C will then be discharged over a circuit which includes the lower plate of condenser C, conductor ZKDs, segment ZSS, brush ZB2, segment ZQI, conductor ZKDi, conductor ZKDz, resistor R5, the armature and contact IVI of relay RR, and the upper plate of condenser C. It is observed that the terminals of tube ZT are connected to resistor R5 and therefore the voltage across condenser C is also applied to the plates of tube ZT. In this instance, however, the lower plate of tube ZT will receive the positive potential previously applied to the lower plate of condenser C, thereby causing the lower plate of tube ZT to become illuminated. The character l of the scanning disk SD will be positioned in front of the lower plate of tube ZT just when it is illuminated so that the character i will become visible to the attendant.

When the pulses corresponding to the character il are received from station A, the first unit spacing pulse moves the armature of relay RR to its Contact S. As brush ZB2 contacts segment ZST, the condenser C becomes vchargedby battery Ba to render the lower plate of condenser C positive with respect to its upper plate, as already explained hereinabove. The first unit marking pulse received from station A will then move the armature of relay RR to its marking contact M. Hence when brush ZB2 contacts segment ZSH, the positive charge on the lower plate of condenser C will remain undisturbed, as explained hereinabove in regard to the reception of the marking pulse of character No. l, at the time when brush ZB2 contacts segment ZSH. When the second unit spacing pulse is received, the armature of relay RR will return to its spacing contact S and hence when brush ZB2 contacts segment ZQI, the charge on condenser C will remain substantially unaffected. This is because the connection of conductors ZKD'i, ZKDZ and Zl'sDs to each other by brush ZB2 and segments ZQi and ZSS will not discharge the condenser C when the armature of relay RR is removed from its contact M. However, when the second marking pulse is received it will move the armature of relay RR to its contact M. Hence when brush ZB2 contacts section ZWZ, the discharge path for condenser C will be completed. Condenser C will then discharge through resistor R5 and tube ZT and will illuminate the lower plate or tube ZT because it has then been rendered sufiiciently positive with respect to its upper plate. The illumination of the lower plate of tube ZT will occur at about the time when character 2 of the scanning disk SD is opposite the illuminated plate. This character will therefore become visible to the attendant. The illumination of tube ZT will cease immediately after the condensers voltage is discharged below the ionization point of the tube even though the character 2 has not passed tube ZT.

Similarly the reception of pulses corresponding to other characters such as 3. d, etc., will illu.- minate the tube Z'I at about the time when the second marking pulse is received. Thus in all cases of 'four-transition characters, the second marking pulse will initiate the discharge of condenser C for a brief, but appreciable time interval and illuminate the lower plate of tube ZT at about the time when the particular character of the scanning disk SD reaches the tube ZT. The tube ZT is stationary. Its position marks a point which is spaced from the various characters of disk SD by peripheral distances which correspond to the interval preceding the final marking pulse received.

If desired all of the characters on disk SD may be spaced fromeach other at shorter intervals so that they may all be conveyed from station A to station B either by two-transition pulses or by four-transition pulses. If only one type of pulse is used, the apparatus will be somewhat simpler and more easily constructed.

It is important to hold any one of the keys of Fig. l, such as key E, depressed until the brush arm passes the segment YES which is connected to contact YE controlled by key E. This will prevent errors in signaling. If this precaution is observed, the apparatus will operate satisfactorily. Y

Instead of a device for the transient illumination of the received character, the receiver may include a printing relay or magnet for printing the characters on a tape. The winding of the printing relay or magnet would then be energized by the condenser discharge current. This relay or magnet might serve to press the tape against the disk SD to print the character adjacent to the relay or magnet. ,The tape may be controlled for step-by-step action by a relay having its winding in series with the resistance Re.

Instead or a device for the transient illumination of the received characters, the receiver may include a` unit for recording the received characters on a nlm or tape. In this case the disk with transp-arent characters would be rotated between the neon tube and a photographic nlm or paper, (not shown) all enclosed in a dark chamber. The film or tape may be controlled for step-,by-step action by a relay having its winding in series with the resistance R3. The light emanating from the neon tube with this arrangement would traverse the transparent contour of any character of the disk SD and cause a portion of the film or paper corresponding to the contour of the received character to be exposed to the light of the tube, thus providing a photographic record of the received characters.

Although the invention has been described as enabling an operator to signal from station A to station B, the arrangement is suitable for twoway signaling between stations A and B (and any other stations).

While this invention has been shown and described in certain particular embodiments merely for illustrative purposes, the invention is vequally applicable to other and widely varied organizations without departing from the spirit of the invention and the scope of the appended claims.

What is claimed is:

l. The combination of a condenser, a gas tube having two electrodes which may be connected across said condenser, a movable display device having different characters to be displayed, means for charging said condenser to either polarity of a predetermined voltage, means for rapidly discharging said condenser through said tube so that one or the other of the electrodes of the tube will become illuminated in accordance with the polarity of said condenser to illuminate saldi movable device only duringthe brief inter-A vall duringi which saldi tube? isv illuminated;` saidY electrodes and said.' movalrlel device: being: so relr atiwaly mounted that" for particular positions of. said mov-able device: said; electrodes are adapted respectively" to: illuminatel andA display diierent characters: carried onsaid movable device..

23 The combination of a condenser; alumihous two-electrode gas tube, a rotaryA device rotating in proximity of said gas tube, meansfor charging said condenser to either polarity of a, voltage" exseedingthe value required.v to. illuminate? said tube; and means for discharging said condenser throughsaid' tube. when said rotary' device' has rota-ted through aA predetermined. angle, one electlrod'e of said tube; being illuminated when said condenser is` charged toone'polar-ity and.r the`l other electrode illuminated when said condenser' is charged tol the oppositeV polarity, said electrodes illuminating one. or the. other off certaini areas on. the` rotary device for a given position.

3". Thecombi'nation of a condenser, a luminous two-electrode gas tubeVa. rotary device.y positioned' adjacent tesa-id gastube, means'vfor rotatingzsaid rotary device and for charging said condenser to either polarity of apredetermined' voltage, means for' discllarging:y said condenser through said' tube wheny said rotary device has'. rotatedtlirouehl a predetermined angle, oneiele'ctrodef of said tube* being illuminated when. sai'd condenser islcnar-gedf to' one polarityand-theotherl electrode illuminated when; said condenser. is: charged; to the opposite polarity andi. markings on said ro'- tary devicearranged in. two series,V the members off' one seriesV being adapted toi be selectively displayed by! theA illumination of one electrode' of sai'd tubel and thel memberslo'r the other series bei'rrg adapted tobe selectively displayedI by the il`- lumi-nation off' the other electrode of.' said tube.`

4'.A The combinations ofacondenser, atwoeelec'- trode luminous gas tube; a resistor? connected in shunt with. the electrodes ofy said. tube, a rotary device: tl`1e=r periphery of-n which is adjacent said gas tube adaptedfordisplay of, different portions of said.4 device. for a. given positiony byY illumination of one orthe' other of the said electrodes', means for rotating saidf` rotary device through onerevolution, means -for' charging said. condenser to either: polarity' of a predetermined voltage: when said rotary device hast-reversed a first predetermined angie; and meansv for discharging said condenser through said.- resistor to illuminate said tube:when'said rotary device-has traversed a second predetermined angle,. one electrode of said tube being. illuminated` when. said condenser is charged: toC one polarity,v and the other electrode illuminatedfwhen said-condenser is charged torthe opposite' polarity.

FRANK` HAROLD' HANLEY.

REFERENCESV (JI-BED A'Ille following references are of record' in the ille of thisl patent:

UNITED STATES PATENTS Number Name' Date 2,006,737 Gessfordl July 2,1935 2,121,005 Nichols` Ang. 16, 1'9'38 2,184,355. llibman Dec. 26, 1939 2278,51"6 Gullikserr Apr. 7, 1942 213463251- Bry'c'e' Apr. 1944 2-.l832389 B'ornson Dec* l2, 1939 2`,32l',60lz Keinath June-15; 1943 FOREIGN. PATENTS Number' Country Date 18d-,017#V Great Britaini 1923 

